Cray Dethrones IBM In Supercomputing

After five years of big iron domination, Big Blue's supercomputing streak is finally over.

At the SC09 conference in Portland, Ore., Tuesday, the "Top500" group of academics and industry watchers plan to officially crown the new fastest supercomputer in the world:
Cray's
Jaguar system, a cluster of nearly a quarter of a million
Advanced Micro Devices
chips housed at the Oak Ridge National Laboratories.

Jaguar, which the U.S. Department of Energy uses for complex problems such as climate change and combustion modeling, is capable of about 50% faster performance than the previous record holder, the
IBM
Road Runner system that first broke the so-called petaflop barrier last summer. With Road Runner and the Blue Gene/L supercomputer before it, IBM had held supercomputing's top spot for five years running.

The Top500 testers clocked Jaguar's number-crunching at 1.75 petaflops, or 1.75 quadrillion floating point operations a second. At that speed, the system would be capable of performing in about nine hours the same work that would take a typical
Intel
-powered laptop around 2,000 years. Despite more than 30 years of supercomputing history, Seattle-based Cray has never before held the top spot on the Top500 list.

The less-than-subtle trick behind the company's coup? Piling on the processing power. Cray upgraded Jaguar earlier this year, switching out each of its four-core AMD chips for a six-core version processor AMD calls Istanbul, bringing the system's total cores to 224,000 from around 150,000. "This is the biggest jump from generation one to two we've ever seen," says Jack Dongarra, a computer scientist at the University of Tennessee and one of the Top500 testers.

Still, Cray Chief Executive Peter Ungaro argues that its upgrade represents more than mere brute force. The limiting factor in systems that cluster hundreds of thousands of x86 commodity chips is often the system's ability to exchange information between the processors. Cray configures its chips in a "torus" shape--resembling two donuts set side-by-side and turned 90 degrees--that maximizes communication from chip to chip. And although Cray, unlike some of its competitors, doesn't build those chips itself, it does design its own interconnect software between those processors. "That's the magic of a Cray machine," says Ungaro. "It's our custom interconnect--something that's Cray's alone--that allows this to be the highest performance machine in the world."

That mass-clustering approach, however, has a price. Jaguar uses about 7 megawatts of energy even before cooling, the equivalent of around $7 million a year if the system were run continuously. IBM claims its Road Runner system, which uses a far smaller number of AMD Opteron processors mixed with around 12,000 of its own Cell gadget processors, burns between 2 to 3 megawatts, cooling included. "Everyone else will at some point catch on that they have to pay attention to the per-watt cost of computing," says David Turek, IBM's vice president for Deep Computing. "The era of simply adding more processors is coming to a close."

Cray's Ungaro points out that IBM's approach has its own disadvantages. Because it uses custom chips rather than the typical x86 platform, he argues that it requires custom programming and is limited to fewer applications.

While IBM and Cray vie for the supercomputing leaderboard's top spot, Big Blue and
Hewlett-Packard
continue to compete for dominance of the list as a whole. HP claimed 210 of the 500 spots, compared with IBM's 186, though IBM claimed the most total performance with 35% of the list's combined processing power.

Meanwhile, a new power has also emerged on this year's supercomputing leaderboard: China. The Tianhe super computer (Mandarin for "Sky River" or "Milky Way") placed fifth on the list, with performance of more than half a petaflop. The Chinese military uses the system, located in Tianjin, to design large aircraft and model petroleum exploration.

IBM doesn't plan on letting any competitor--foreign or domestic--take its top spot for long. By 2011, the company has promised to deliver a system known as Sequoia, whose projected 20 petaflops would add up to more than the rest of the current list combined. (See: "IBM Promises World's Fastest Supercomputer--Again")

Cray says it's not about to cede the race. "Of course it's IBM's approach to talk about the future if they're not No. 1 today," Ungaro says dryly. "You can be sure that, by 2011, we'll have broken even more records."